Omega MV6 Knocking at Low Revs

Hello,

Can anyone offer some advice?

My R reg Omega 3.0 MV6 has been developing a knocking noise which is
loudest when sat in the drivers seat with the engine ticking over. It
either goes away or at least reduces as soon as you give it any revs.
It doesn't happen when the engine is cold becasue (i think) the rev's
dont drop low enough.

I've checked the exhaust and had a general look around the engine but
cant see anything or pin point the source of noise. It seems to have
got worse over a course of a few weeks, and now its really starting to
bug me.

Any ideas?

 

Kock or tick?

If it's a tick, could be tappets.

If it's a knock:
Fucked oil pump.
Worn big end bearings.
Worn Main Bearings.

 

Big Ends, at worst >

 

A tick could also be an exhaust manifold gasket. They do fail sometimes
and it usually quietens down when it warms up. Get a short length of
hose pipe and stick one end to your ear and see if you can locate where
it's coming from.

Could also be your oil pump not forcing enough oil to the tappets when
it's idling while hot, about 500 rpm. Is your oil good, nice and clean?

 

yep thats my fav method too
though i use yee olde 2ft giant flatblade driver to my ear, then push it
around on the engine casing till i find it and feel it usually 100%
accurate too!
when was the last oil change? as the gent says.
not too fam with your engine, but how about a belt/drive chain being loose?

the 3ltr sintra engine is known to get noisey in summer months i seem to
reacall reading in a tech bul sometime ago.
not that one is it?

mike

 

If you really want to pin things down get one of these:

<http://www.machinemart.co.uk/shop/product/details/cht171-mechanics-stethoscope>

Only a fiver and they work *really* well.

 

They do work well. I found the rumble on my aux belt idler pulley with
that. Not good at finding a manifold leak though because that's coming
into the air. You can hear all the internal bits in the engine though
but nothing to match the tick of the manifold. The manifold in the V6
do crack on occasion as well.

 

I have about 3 foot of clear walled flexible plastic tubing, similar to the
battery breather tubes found on motorcycles. One end has an old drill bit
pushed in as a snug fit, the other open end goes in my ear. Not so much a
stethoscope, more a monoscope. Works fine and a lot easier to use than a big
screwdriver, but I have also done that as well in the past!

Mike

 

Its more of a nock or clunk than a tick. The thing is, that is
doesn't seem to be coming from the top end, so i dont think tappets.
I hardly drove the car over the long weekend, and it was fine the next
day, but then the day after it was back to its normal knocking. I'll
definately try the monoscope idea tho and have a good poke about.
Thanks for all the suggestions!!

 

Last full oil change was just over 2500 miles ago, however she does
burn a bit of oil, and needs a 1/4 pint top up every 2-3 months.

 

Check the bottom pulley is tight and hasn't become separated at it's rubber
bonding.